This invention relates to an improved noise barrier construction and method of making and installing the same.
Various noise barrier systems have been devised to control noise pollution emanating from express highways, railroad tracks or factories. Many such systems include combinations of noise insulating materials, air space, and noise reflective plates. Examples of such systems which have heretofore proposed are shown, for example, in European Patent Application No. 039984 published Nov. 18, 1981, West German Patent Application No. DE3043876 published Sept. 9, 1982, West German Patent Application No. DE3300024 published July 5, 1984, West German Patent Application No. 2343617 published Aug. 27, 1973, U.S. Pat. No. 4,605,090 issued Aug. 12, 1986, and U.S. Pat. No. 3,630,310 issued Dec. 28, 1971.
In some of the prior art systems, the barrier panels are suspended above the earth. Such constructions permit noise to pass under the barrier. Another common construction involves the pouring of horizontal concrete bases to support the wall panels. The concrete surfaces, however, have been found to reflect most of the noise to the opposite side of the highway or other noise source. The use of such poured concrete bases is, moreover, costly and the resultant walls in hilly terrain have a stepped appearance with substantial sound reflective wall or step areas of concrete in addition to the barrier panels which are mounted above such footings.
Some systems such as those shown in U.S. Pat. No. 4,605,090 and German Application No. 3043876 have proposed the formation of concrete bases and panels that would be shaped to follow the contour of the earth. Such constructions, however, have been found to have shortcomings in terms of difficulty of manufacture and installation. Additionally, with many proposed prior art designs there is difficulty in obtaining adequate resistance to wind stresses encountered by such structures. A need has therefore continued to exist for improved sound barrier systems which are easy to assemble in commercial quantities and simple to install. It is the primary object of the present invention to fulfill this need. Other objects of the invention include providing a sound barrier system with increased sound absorbing characteristics and to provide such a system which can be easily assembled with a minimum of labor expense. A significant aspect of the invention relates to the elimination of the need for a concrete base for the sound barrier, the use of such bases having become standard in the industry. Further, objects and advantages will be apparent from the accompanying descriptions of the invention and drawings.